Background & aims: It has been suggested that irritable bowel syndrome (IBS) and functional dyspepsia represent the same disease entity, the irritable gut. The aim of this study was to test the stability, consistency, and relevance of the current classification in the entire, unselected population of persons with gastrointestinal and/or abdominal symptoms, including those who had not consulted physicians.
Methods: Sequential postal questionnaires were sent to 1290 representative persons (age range, 20-79 years) sampled from the population. Questions were asked about the prevalence of 24 gastrointestinal and/or abdominal symptoms and the site and type of abdominal pain, if any.
Results: The prevalence of dyspepsia was 14% (32% if predominant reflux symptoms and concomitant IBS symptoms were included), and the prevalence of IBS was 12.5%. The 3-month incidence rates of reflux, dyspepsia, and IBS among previously symptomless persons were 0.5, 8, and 2 per 1000, respectively. Of persons with IBS, 87% also fulfilled the dyspepsia criteria, and the overlap between dyspepsia subgroups was more than 50%. The use of stricter criteria did not eliminate this overlap. Over a 1-year period, approximately 50% changed their symptom profile. Principal component analysis did not show any natural clustering of the symptoms.
Conclusions: The separation of functional gastrointestinal symptoms into dyspepsia, its subgroups, and IBS may be inappropriate.